Eyewear including eyeglasses and goggles for various purposes conventionally include a frame structure made of substantially rigid material such as a rigid plastic material, with one or two lenses attached thereto. The frame structure is used to support the lens or lenses thereon and is configured in accordance with, and abuts the eyewear users face around or near the eyes. The frame structure is retained on the users head by a side piece or pieces, for example, temples or an elastic strap. Some eyewear such as eyeglasses or goggles for sports or safety, may suffer to some degree from fogging of the lens or lenses due to the perspiration and warmth emanating from the user's face. To solve this problem, manufacturers of eyewear have included vents in the eyewear frame structure to allow moisture and heat to escape from the space between the eyewear and the user's face. Efforts have been made to design vent structures which prevent foreign substances such as dust and liquids from flying through the vents and impacting the user's face or even entering the user's eyes. In addition, modern eyewear requires eyewear frame structures in complicated geometries and may be made of more than one material, which presents additional challenges for eyewear manufacturers to provide vents in such modern eyewear frame structures.
Therefore, there is a need for improved eyewear frame structures having vents which allow ventilation but prevent foreign particles from being carried in the airflow to impact on a user's eyes and face.